England pulled off a bonus point victory over Fiji in the opening match of the 2015 Rugby World Cup, but they will know there is plenty of room for improvement

England fullback Mike Brown scores a try against Fiji in their 2015 Rugby World Cup matchReuters

There were moments in the match when you thought "hey, we might have an upset here" but in the end, England saw off the challenge of Fiji to open their 2015 Rugby World Cup campaign with a victory in front of a raucous Twickenham crowd.

Being the hosts always brings the extra pressure, and that pressure was felt by England in phases in this match, but key moments, particularly errors from Fiji, eventually proved to be the difference.

The final score of 35-11 – a margin that gives the home team a bonus point as well, thanks to a late try -- might look comfortable for England, but it did flatter them a little bit, something that coach Stuart Lancaster acknowledged.

"We need to improve, there's no doubt," the head coach said. "We're going to have to look at a couple of areas ... we didn't get as much clean set-piece ball as we would want and Fiji were very competitive at the breakdown. We need to be more direct, to be honest. We were too lateral in the first half, particularly after the first 20 minutes. We also need to look at some of the accuracy of our decision-making at the breakdown.

"It wasn't the nicest position to be in but I was always confident the players were in control," Lancaster added when asked about how confident he felt when Fiji was just seven points off England at one point. "I don't think they ever really broke us down defensively.

"But if we'd been offered four tries and a bonus point before the game I'd absolutely have taken it. We won't be the only team Fiji will cause problems to in this tournament."

Fiji coach John McKee rued the fact that his team made some crucial mistakes in the match, which eventually cost them the chance of potentially causing a massive upset. "England will be looking at it and saying they have to sharpen up for Australia and Wales," McKee said. "At times we felt we had England under pressure but critical penalties and critical errors let them back into the game."

While the England performance might not have been entirely convincing, what was undoubted was the crowd support, with Twickenham creating an atmosphere that will gee up any home team, while sending a shiver down the opposition's spine.

"The whole thing was phenomenal as an occasion," Lancaster said about the support. "Twickenham was rocking when we arrived.

"We couldn't hear much in the changing rooms ... the boys were like caged animals because normally they'd be out on the field warming up. I think that built up the nerves a bit and we took a while to settle."